builder/vmware: only unregister if registration success

builder/vmware/step_run.go

@@ -20,6 +20,8 @@ import (
 type stepRun struct {
 	bootTime time.Time
 	vmxPath  string
+
+	registered bool
 }
 
 func (s *stepRun) Run(state multistep.StateBag) multistep.StepAction {
@@ -49,6 +51,8 @@ func (s *stepRun) Run(state multistep.StateBag) multistep.StepAction {
 			ui.Error(err.Error())
 			return multistep.ActionHalt
 		}
+
+		s.registered = true
 	}
 
 	if err := driver.Start(vmxPath, config.Headless); err != nil {
@@ -91,11 +95,13 @@ func (s *stepRun) Cleanup(state multistep.StateBag) {
 			}
 		}
 
-		if remoteDriver, ok := driver.(RemoteDriver); ok {
+		if remoteDriver, ok := driver.(RemoteDriver); ok && s.registered {
 			ui.Say("Unregistering virtual machine...")
 			if err := remoteDriver.Unregister(s.vmxPath); err != nil {
 				ui.Error(fmt.Sprintf("Error unregistering VM: %s", err))
 			}
+
+			s.registered = false
 		}
 	}
 }